This invention relates to the application of end fittings to wire strand. More particularly the present invention relates to the application of lubricant to the area of the junction between the end of a poured socket attachment or end fitting and the wire strand after the application of the fitting to the strand.
There are three principal methods for applying a socket type end fitting to wire strand. In the first method the end fitting or socket is secured to the end of the strand by means of a solidified low melting socketing metal such as zinc or zinc alloy which is poured while in a molten condition into the bowl of the socket subsequent to insertion of the end of the strand into the socket. In the second method the end fitting is secured to the end of the strand by means of a solidified organic resin, for example, an epoxy resin material, which is poured while in a cool fluid condition into the bowl of the socket and cured with or without heat subsequent to insertion of the end of the strand into the socket. In the third method a deformable socket or end fitting is compressed upon the end of the wire strand by swaging or other mechanical compression.
Socketing by the use of hot metals such as zinc, zinc alloys or other low melting metal alloys or by the use of organic resin materials such as epoxy resins or the like are broadly referred to hereafter as socketing by the use of a solidified liquid. The socket used for either type of socketing, which socket may be the same whether a hot metal or an organic resin is used, is referred to broadly hereafter as a poured socket attachment or end fitting.
Some strand sockets are not suitable for resin socketing because it has been found that resin sockets should have a wedge shaped interior section to maintain the resin under compression when tension is applied to the strand. Consequently, if resin socketing is to be used for applying end fittings to wire strand, either a specially designed strand socket with a full internal wedge action or a wire rope socket may be used on the wire strand.
When using poured socket attachments or end fittings the end of the wire strand must prior to socketing be cleaned to remove all oil, dirt and grease from the component wires. The wires are then "broomed out", or separated in the bowl of the socket and the molten socketing metal or cool fluid organic resin socketing material is poured into the upended socket and allowed to solidify about the broomed out wires. If the wires were not initially cleaned to remove oil and grease the bond of the solidified socketing metal or solidified organic socketing resin with the wires would be adversely affected. Most of the oil and grease present on the wire strand comes from the strand lubricant. This lubricant normally lubricates the strand and prevents the component wires from binding and abrading against each other during use of the strand. Binding and abrading not only wears the wires away and increases fatigue but since most wire strand is comprised of either zinc or aluminum coated ferrous wires, or alternatively a new aluminum-zinc alloy coating only recently developed for use on wire, any abrasion between the wires tends to abrade away the coating exposing the underlying base metal to corrosion. It is thus very important that strand lubrication be maintained. Even if no corrosion resisting outer metal or other coating is provided on the component wires of the strand the normal strand lubricant tends to retard corrosion and if the strand lubricant is missing from the wires at any point there will tend to be additional corrosion at that point.
Strand lubricant is normally applied either during stranding of the wires together in the stranding die or sometimes shortly thereafter when additional lubricant is applied by passing the strand through a bath of lubricant. It is very difficult to apply the lubricant to the inner wires of the strand once the wires have been stranded together, however. Consequently, most, if not all, of the lubricant on the internal wires of the strand is applied as the wires enter the stranding die.
As previously stated, prior to hot metal socketing or cool fluid organic resin socketing of a wire strand, the strand lubricant must be removed from the portion of the wires of the strand which will be contacted by the hot metal or resin. This is usually accomplished by dipping or otherwise exposing the portion of the end of the strand which will be encased in the socket to a solvent for the lubricant. In order to make certain that lubricant does not touch the hot socketing metal causing burning and carbonation which might adversely affect either the strength of the wires of the strand, the bond of the socketing metal with the surface of the wires, or the protective metal coating on the wires the lubricant is cleaned from the strand for a short additional distance such as a centimeter or so beyond the point at which the hot metal is expected or calculated to contact the wires. The lubricant must also be removed from this short section to prevent lubricant from seeping back into the socket portion of the strand during hot metal socketing. Likewise, in order to assure a proper bond between organic socketing resin and the surface of the wires, or any protective metal coating on the wires, the lubricant is cleaned from the strand for a short additional section such as a centimeter or so beyond the point at which the resin is expected or calculated to contact the wires. The lubricant must also be removed from this short section to prevent lubricant from seeping back into the socket portion of the strand during the pouring of the liquid organic resin into the bowl of the socket.
After socketing is completed attempts are often made to relubricate the section of the strand near the neck or base of the socket, usually by squirting or otherwise applying lubricant to the exterior of this section. While the exterior wires of the strand can be effectively lubricated in this manner, it is extremely difficult, if not impossible, to reapply lubricant to the internal wires.
It is therefore an object of the present invention to provide a fatigue and corrosion resistant flexible linear assembly comprised of a wire strand with a poured socket attachment or end fitting with provision to lubricate the portion of the strand adjacent the end fitting in order to reduce fatigue and other failure of the strand during use.